Biomechanical considerations in the design of high-flexion total knee replacements

Abstract

Typically, joint arthroplasty is performed to relieve pain and improve functionality in a diseased or damaged joint. Total knee arthroplasty (TKA) involves replacing the entire knee joint, both femoral and tibial surfaces, with anatomically shaped artificial components in the hope of regaining normal joint function and permitting a full range of knee flexion. In spite of the design of the prosthesis itself, the degree of flexion attainable following TKA depends on a variety of factors, such as the joint's preoperative condition/flexion, muscle strength, and surgical technique. High-flexion knee prostheses have been developed to accommodate movements that require greater flexion than typically achievable with conventional TKA; such high flexion is especially prevalent in Asian cultures. Recently, computational techniques have been widely used for evaluating the functionality of knee prostheses and for improving biomechanical performance. To offer a better understanding of the development and evaluation techniques currently available, this paper aims to review some of the latest trends in the simulation of high-flexion knee prostheses.

Figure 1

Femoral and tibial components modified on both medial and lateral sides [18]. (a) Anatomic-like knee, (b) knee with condyle height difference of 2.7 mm, and (c) knee with condyle height difference of 4.7 mm.

Figure 2

Initial engagement and the imaginary overlap between the tibial post and femoral cam for flat-on-flat (a) and curve-on-curve (b) models [28].

Figure 3

Contact stress (MPa) on the anterior face of tibial post at 10° hyperextension and 5° axial rotation for (a) flat-on-flat and (b) curve-on-curve contact surfaces (modified from [30]).